The present invention relates generally to oilfield drill-pipe handling equipment and, more particularly, to an apparatus and method for quickly and efficiently mating drill-pipe handling equipment housed in a pipe shelter facility with hoisting and other handling equipment mounted in an adjacent, housed portable drilling module.
During oil field drilling and workover operations, it is necessary to make up and break down long strings of tubular goods such as drill pipe. Drill-pipe sections may be stored horizontally in racks in, say, a drill-pipe shelter. The drill pipe must be transferred from the storage racks where the pipe rests horizontally to the drilling module where the pipe will be used in a vertical position to make up a pipe string.
In some locations, especially on the North Slope in Alaska, it is desirable to use highly portable drilling rigs. These rigs are enclosed to protect workers from the hazards of the extremely cold temperatures. One arrangement is to componentize the drilling rig into three basic modules, viz.,: (1) a drilling module that includes a hoist for raising and rotating the pipe string, a rotary table for driving the drill string during drilling operations, and various auxiliary equipment; (2) a mud module for containing and supplying drilling fluids and for providing other services to the drilling setup; and (3) a pipe shelter for storing and delivering drill-pipe sections. In setting up the drilling or workover operation, the drilling module is set in place over the well-bore, and the mud module and the pipe shelter are brought into place adjacent the drilling module. These modules may be self-powered or constructed on trailers which may be towed by oil-field trucks or tractors.
The pipe shelter may have within it a ramp structure to facilitate transfer of pipe sections into the drilling module and to received pipe sections from the drilling module. The drilling module may have within it an extension of the ramp structure to continue to guide the pipe sections as they are moved from the pipe shelter. During setup of the drilling rig, the ramp structure within the pipe shelter must be carefully aligned with the ramp extension in the drilling module to facilitate a smooth path for pipe moving from the ramp in the pipe shelter to the hoisting mechanism in the drilling module. Alignment can be time consuming and tedious because the pipe shelter may be built on a large trailer towed by an oil-field truck, and the truck may have to be moved back and forth a number of times before drilling module and the pipe shelter properly have their respective components satisfactorily aligned. Such an operation can take two to three hours. When workover is required on a number of well in an oilfield, proper alignment of the modules comprising the drilling rig can add substantial time to the job and consequently add significant cost the job. Further, when workover operations are being performed in inclement conditions, such as on the North Slope of Alaska, this alignment operation may add substantial time of exposure to the oilfield workers with a corresponding increase in risk.
Further, as drilling pipe is moved from the pipe shelter into the drilling module, thousands of pounds of pipe are shifted from one structure into the other. The reverse is true as a drill string is removed from the well-bore. This shift of weight is believed to cause a shift in the relative positions of the drilling module and the pipe shelter. This results in loss of alignment or registration between the pipe ramp in the pipe shelter and the ramp extension in the drilling module. More importantly, subsidence can occur in gravel surface cover or due to softening of the permafront in warm weather in arctic areas. Subsidence may result in substantial misalignment of the modules. This may require adjustment of the position of the pipe shelter which again may be time consuming, costly, and hazardous to the oilfield workers. Sufficient misalignment of the pipe ramp and its extension may even result in damage to the drill pipe and other tubular goods such as casing and production tubing which may add substantially to the overall cost and risk of hazard on the job.
It would therefore be advantageous to provide an apparatus and method to align selected components in a drilling module and a pipe shelter without having to move either relative to the other. It would also be advantageous to permit the quick and easy aligning of a pipe ramp in a pipe shelter with a pipe extension in a drilling module. It would further be advantageous to provide a means to maintain proper alignment and registration between a pipe handler and a ramp extension in a drilling module as a pipe string is transferred in a first direction from one structure to the next and then in a second, opposite direction.